Contactless Adjustable Tensioner for Craft Spinning Apparatus

ABSTRACT

A hobbyist spinning apparatus uses a position-adjustable permanent magnet to induce eddy currents in a rotating conductive disc. The eddy currents oppose the rotation, and the opposing (braking) force applies a consistent tension to a fiber yarn being wound onto a bobbin.

CONTINUITY AND CLAIM OF PRIORITY

This is an original U.S. utility patent application that claims priorityto U.S. Provisional Patent Application No. 62/182,038 filed 19 Jun.2015.

FIELD

The invention relates to machines for spinning fibers into yarn. Morespecifically, the invention relates to an adjustable tensioner for amanually-operated spinning wheel.

BACKGROUND

A variety of machines have been conceived to assist in manufacturingyarns from bulk fiber, and for preparing those yarns for further use inmaking textiles by knitting, weaving and other techniques. These may bereferred to generically as “spinning wheels.” Large-volume,industrial-use machines have progressed far beyond the manually-operatedspinning wheels of old, but manual and modest-capacity automaticmachines are still popular among hobbyists, artists, and for spinningyarn from unusual fibers of limited large-scale commercial value.Improvements to the latter type of machine may increase hobbyist'senjoyment of textile crafts and permit them to make better, more uniformyarns and fabrics.

SUMMARY

Embodiments of the invention use a non-contact mechanism to apply acontrollable braking force to a rotational movement. In one aspect, apermanent magnet adjustably disposed near a rotating conductive discapplies the controllable braking force. In another aspect, a fan orturbine compresses air into a chamber from which an adjustable orificeallows it to escape. The braking force is proportional to tension on ayarn or thread being twisted and wound onto a spool. Consistent tensionhelps produce a uniform yarn and allows the spool to be wound smoothlyfor improved characteristics during subsequent use.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a partial cutaway view of a representative embodiment ofthe invention.

FIGS. 2-6 are photos from various vantage points of an electric spinningmachine incorporating an embodiment of the invention.

DETAILED DESCRIPTION

Spinning wheels wind twisted fiber (yarn) onto a spool. To achieveuniform spooling, the tension in the yarn as it is wound should bemaintained at a relatively constant level. This is typicallyaccomplished by turning the feed mechanism or “flyer” faster than thebobbin, so that the yarn from the flyer pulls the bobbin along (thustensioning the yarn). Or, from another perspective, the bobbin may beretarded or braked, so that tension in the yarn pulls it along.

Embodiments of the invention brake the bobbin using a non-contactmeans—that is, by a mechanism that does not use mechanical frictionbetween two surfaces to provide braking. Alternate embodiments useelectromagnetic fields or air pressure, as described below.

FIG. 1 shows a partial cutaway view of a representative embodiment ofthe invention. In a spinning machine, a frame 100 supports a flyer 110and a bobbin 120 so that they can rotate about a common axis 130. Theflyer 110 and bobbin 120 rotate in the same direction, but at slightlydifferent speeds. The user feeds fiber 140 into the Y-shaped flyer 110through the stem of the Y; rotation of the flyer imparts a twist to thefiber, turning it into a twisted yarn. The yarn passes through guides152, 154, 156 before being spooled onto bobbin 120. In a preferredembodiment, guide 156 is configured to advance and retreat along an armof the flyer so that the yarn is deposited evenly across the length ofthe bobbin. (See, e.g., U.S. Pat. No. 4,458,474 to inventor Robert Lee.)In other embodiments, guide 156 may be stationary (but adjustable). Insuch an embodiment, the user may stop the apparatus occasionally toadjust guide 156 so that yarn is wound onto a different portion of thebobbin.

To achieve uniform spooling of the fiber, steady tension should beapplied to the yarn as it passes from the last guide on the flyer to thebobbin during spinning. This is traditionally accomplished throughfriction braking of at least one of the flyer 110 and bobbin 120. Forexample, a loop of string or fishing line (monofilament) may betensioned over a groove in the bobbin or flyer to provide drag. However,this arrangement is inconvenient when changing bobbins, and at higherspinning speeds, the string experiences friction heating and can breakor burn through.

An embodiment of the invention provides adjustable drag or braking onthe flyer or bobbin by coupling the braked component to turn along witha conductive disc 160 (shown connected to the bobbin in thisillustration), and providing a permanent magnet 170 that can bepositioned at an adjustable distance from the conductive disc. (In thisFigure, adjusting control 180 back and forth moves magnet 170 closer orfurther from conductive disc 160.) The permanent magnet induces eddycurrents in the conductive disc, and these currents oppose the forcerotating the bobbin. Thus, although there is no contact between the discand the magnet, an adjustable braking force can be applied to maintainsteady winding tension.

The conductive disc may be, for example, an aluminum, brass, copper orsteel disc. Conductive plastics and other materials may be employed aswell. Both ferromagnetic (e.g. iron or steel) and non-ferromagnetic(aluminum, brass, copper) materials may be used. The disc may take adifferent form, such as the “squirrel cage” rotor of analternating-current (“AC”) electric induction motor.

It is appreciated that the conductive-disc and magnet apparatus behavessomewhat like an alternating-current motor being operated in aregeneration or braking mode. In fact, instead of a permanent magnet, anembodiment may provide one or more electromagnets (wire coils) that,when energized, induce the eddy currents that provide braking. Thecontrol system to perform commutation of the coils makes this embodimentmore complex, but if controllable commutation is provided, thenmechanical motion of a permanent magnet (closer or further from thedisc) may be omitted: the braking force can be controlled by advancingor retarding the commutation timing instead of changing a mechanicalgap. Furthermore, in an embodiment that uses controllable commutation toinfluence the conductive disc via suitable electromagnetic fields, thecommutation could act to accelerate rather than brake the conductivedisc. In effect, the conductive disc serves as an electric motor, urgingthe flyer or bobbin to spin faster than the other component so that theyarn is held under tension as it winds on.

In another embodiment, conductive disc 160 may be replaced by a fan orturbine, which draws atmospheric-pressure air into the machine andforces it into a closed chamber. The chamber has an adjustablepressure-relief valve, and the braking force provided by the apparatusis controlled by the spinning speed and the pressure. In thisarrangement also, braking is accomplished without contact or mechanicalfriction.

Mechanical power to spin the bobbin and flyer can be applied to theapparatus in any conventional way. For example, a pedal-actuated belt,string, chain or gear train may be provided, or an electrical motor canbe connected to the drive train.

In some embodiments, the disc-magnet distance (and corresponding brakingforce) may be adjusted manually by a linear or rotating threadedcontrol. In other embodiments, the disc-magnet distance may be adjustedautomatically, under the control of a servo or similar actuator. Anautomatic adjustment system may incorporate a measurement of presentfiber tension in a feedback loop, thus allowing consistent tensioning asthe diameter of the bobbin increases (because of different bobbingeometries or because the bobbin diameter increases as more yarn iswound on).

FIG. 2 is a photo of a prototype similar to the structure depicted anddescribed in FIG. 1. This partial view shows the conductive disc, thepermanent magnet and its adjustment mechanism, and a portion of a bobbinand flyer.

FIG. 3 shows another view of the same prototype. In this photo, thecomplete flyer and bobbin are visible, as is an electric motor fordriving the spinning apparatus and an electronic speed control for themotor. In an embodiment where such electronic control is present, thecommutated-electromagnet braking/tensioning arrangement could be addedrelatively easily. (For a fully-manual embodiment, themanually-adjustable braking from a permanent magnet may be preferred.)

FIG. 4 is another view of the conductive disc and bobbin assembly. FIG.5 shows a front view of the prototype embodiment, and FIG. 6 shows theprototype in operation (note that the flyer is spinning so rapidly thatit cannot be seen clearly in this picture. These figures show a hobbyistelectric spinning machine where the flyer is driven at an adjustablespeed by an electric motor to twist the fibers fed by the user and windthe resulting yarn onto the bobbin. The bobbin is pulled along by theyarn winding onto it, but is braked or retarded to tension the yarn by anon-contact mechanism such as described above. The braking force can beadjusted by moving a permanent or constant-value electromagnet near aconductive disc or rotor, or by active commutation among a plurality ofelectromagnets. Adjustment can be done manually, or automatically by afeedback loop that senses back EMF in the commuting electromagnets andadjusts the commutation to achieve a target tension.

The applications of the present invention have been described largely byreference to specific examples and in terms of particular allocations offunctionality to certain hardware and/or software components. However,those of skill in the art will recognize that adjustable uniform tensionby contactless, electromagnetic braking can also be achieved bystructures that distribute the functions of the illustrated componentsof the invention differently than herein described. Such variations andimplementations are understood to be captured according to the followingclaims.

I claim:
 1. An adjustable tensioner for a spinning wheel, comprising: aY-shaped flyer having a yarn guide on one arm of the Y; a cylindricalbobbin with flanges at either end; a frame arranged to hold thecylindrical bobbin and the Y-shaped flyer on a common axis about whichboth the cylindrical bobbin and the Y-shaped flyer can rotate, thecylindrical bobbin being disposed between arms of the Y; a conductivemember coupled to one of the Y-shaped flyer or the cylindrical bobbin sothat the conductive member rotates with the one of the Y-shaped flyer orthe cylindrical bobbin; and a permanent magnet held by the frame so thata distance between the permanent magnet and the conductive member may beadjusted.
 2. The adjustable tensioner of claim 1 wherein the conductivemember is a circular disc.
 3. The adjustable tensioner of claim 1wherein the conductive member comprises at least one of aluminum,copper, brass or steel.
 4. The adjustable tensioner of claim 1 whereinthe conductive member is a non-ferromagnetic metal.
 5. The adjustabletensioner of claim 1 wherein the yarn guide on one arm of the Y isconfigured to automatically advance and retreat smoothly along the onearm of the Y.
 6. The adjustable tensioner of claim 1 wherein the yarnguide on one arm of the Y is manually adjustable in position along theone arm of the Y.
 7. A spinning wheel with an adjustable tensioner,comprising: a rotating bobbin to wind spun yarn; a feed mechanism toconvey the spun yarn onto the rotating bobbin; a drive mechanism tocause the rotating bobbin and the feed mechanism to rotate; andadjustable tensioning means for altering a rotation of one of therotating bobbin or the feed mechanism without physical contact to causesaid altering.
 8. The spinning wheel of claim 7 wherein the adjustabletensioning means is coupled to the rotating bobbin.
 9. The spinningwheel of claim 7 wherein the adjustable tensioning means is coupled tothe feed mechanism.
 10. The spinning wheel of claim 9 wherein the feedmechanism is a Y-shaped flyer.
 11. The spinning wheel of claim 7 whereinthe adjustable tensioning means is a conductive disc adjacent apermanent magnet, said conductive disc coupled to rotate with either therotating bobbin or the feed mechanism.
 12. The spinning wheel of claim 7wherein the adjustable tensioning means is a conductive disc adjacent anelectromagnet, said conductive disc coupled to rotate with either therotating bobbin or the feed mechanism.
 13. The spinning wheel of claim 7wherein the adjustable tensioning means is an AC induction motor rotoradjacent an electromagnet, said rotor coupled to rotate with either therotating bobbin or the feed mechanism.
 14. An electric hobbyist spinningwheel comprising: an electric motor; a Y-shaped flyer driven by theelectric motor; a bobbin; a conductive disc coupled to the bobbin; aframe to hold the Y-shaped flyer and the bobbin so that they can rotateon a common axis, the bobbin positioned between arms of the Y-shapedflyer; and a magnet adjustably positioned near the conductive disc,oriented to oppose rotation of the conductive disc and the bobbincoupled thereto without physical contact between the magnet and theconductive disc.